Zhiguang Xu

High internal phase emulsion (HIPE) xerogels for enhanced oil spill recovery

Oil spills cause serious damage to the aquatic ecosystem and require quick cleanup. Herein we report high internal phase emulsion (HIPE) xerogels for the first time as oil absorbents for enhanced oil spill recovery. The HIPE xerogels absorb diesel from the water–oil mixture in 20–30 seconds. The absorption capacity of the HIPE xerogels ranges from 20 to 32 times for different kinds of oils, and the oils can be recovered simply by being squeezed out, with a recovery rate around 80%. They can be reused at least 40 times without obvious deterioration in oil separation properties from 0 to 45 °C. These novel xerogels are suitable for practical use in oil spill reclamation and wastewater treatment.

Closed-cell and open-cell porous polymers from ionomer-stabilized high internal phase emulsions

We firstly present a strategy that enables fabrication of both closed-cell and open-cell porous polymers (polyHIPEs) from high internal phase emulsions (HIPEs) stabilized with an ionomer, namely sulfonated polystyrene (SPS). Closed-cell polyHIPEs (St-polyHIPEs) were formed with styrene as the continuous phase in “parent” HIPEs whereas open-cell polyHIPEs (BA-polyHIPEs) were obtained with butyl acrylate as the continuous phase. The average diameters of pores in closed-cell St-polyHIPEs are 91.6 and 68.9 to 42.7 μm corresponding to the increase of the dispersed phase from 75 and 80 to 83 vol% in “parent” HIPEs, respectively. The surface of these closed pores is rough with scars, and the average number of scars per pore increases from 1.6 to 5.3 with increasing the ionomer concentration from 0.2 to 1.5%. The average sizes of both pores and windows in open-cell BA-polyHIPEs increase with the increasing content of the dispersed phase. The average diameters are 39.5, 48.5 and 65.3 μm for pores and 5.3, 7.8 and 13.4 μm for windows, corresponding to 75, 80 and 83 vol% of the dispersed phase in “parent” HIPEs. Amphiphilicity of these polyHIPEs can be reversibly and simply tuned by dipping them into solutions with different pH values, demonstrating that the ionomer is not removed during the purification. Ionomer-stabilized HIPEs provide a new approach for control over the size and interconnectivity of pores as well as the surface roughness and amphiphilicity of resultant porous polymers.

Emulsion-templated, macroporous hydrogels for enhancing water efficiency in fighting fires

We present hydrogel polyHIPEs for enhancing water efficiency in fighting fires. The hydrogel polyHIPEs with interconnected macroporous structures have been fabricated from oil-in-water high internal phase emulsion (HIPE) templating. Hydrogel polyHIPEs exhibit high water uptake and rapid water absorption, reaching hundreds of their dry weights in one minute. Hydrogel polyHIPEs show excellent cooling effect, and the high water uptakes and rapid absorption are well preserved after four cycles of partially drying-absorption. The water requirement and extinguishing time are significantly reduced, demonstrating hydrogel polyHIPEs to be an excellent candidate for enhancing water efficiency in fighting fires.

Granular Nanostructure: A Facile Biomimetic Strategy for the Design of Supertough Polymeric Materials with High Ductility and Strength

The realization of high strength, large ductility, and great toughness for polymeric materials is a vital factor for practical applications in industry. Unfortunately, until now this remains a huge challenge due to the common opposing trends that exist when promoting improvements in these properties using materials design strategies. In the natural world, the cuticle of mussel byssus exhibits a breaking strain as high as 100%, which is revealed to arise from an architectural granular microphase-separated structure within the protein matrix. Herein, a facile biomimetic designed granular nanostructured polymer film is reported. Such biomimetic nanostructured polymer films show a world-record toughness of 122 (± 6.1) J g-1 as compared with other polyvinyl alcohol films, with a breaking strain as high as 205% and a high tensile strength of 91.2 MPa, which is much superior to those of most engineering plastics. This portfolio of outstanding properties can be attributed to the unique nanoscale granular phase-separated structure of this material. These biomimetic designed polymer films are expected to find promising applications in tissue engineering and biomaterials fields, such as artificial skin and tendon, which opens up an innovative methodology for the design of robust polymer materials for a range of innovative future applications.